Semiconductive Cable Polymer Composition for Carbon Black Dispersion
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Solution Overview
Problem
Existing semiconductive polymer compositions for power cables face challenges in achieving a balance between surface smoothness and volume resistivity, particularly with furnace carbon black, which has high volume resistivity and poor dispersion properties, leading to issues like uneven particle size distribution and increased resistivity.
Innovation Solution
A semiconductive polymer composition with a specific range of carbon black properties, including mass pellet strength, individual pellet hardness, and average pellet size, is used to improve surface smoothness and dispersibility, maintaining excellent volume resistivity, even at high carbon black content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the particle size of carbon black is increased to improve surface smoothness, then surface smoothness is improved, but volume resistivity increases (deteriorates)
Solution Approach 1:
The patent applies parameter changes by precisely controlling carbon black particle size within a specific range (0.5-5 μm) and adjusting the distribution of different particle sizes to achieve optimal balance between surface smoothness and volume resistivity. The invention changes physical parameters of carbon black (particle size, particle size distribution) to resolve the contradiction between surface smoothness and electrical conductivity.
Solution Approach 2:
The patent applies local quality by creating different particle size distributions in different aspects: using smaller particles (0.5-2 μm) for surface smoothness and larger particles (2-5 μm) for maintaining volume resistivity. The composition includes carbon black particles with different size ranges to simultaneously satisfy both surface quality and electrical conductivity requirements in different locations/functions of the semiconductive layer.
2Reliability
If furnace carbon black is used to achieve high volume resistivity, then volume resistivity is improved, but dispersion properties deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the surface area of carbon black particles within a specific range (10-50 m²/g) and adjusting particle morphology parameters to improve dispersion properties while maintaining high volume resistivity. The invention modifies physical parameters of furnace carbon black to achieve both good dispersion and high resistivity.
Solution Approach 2:
The patent applies composite materials by combining furnace carbon black with specific polyolefin matrices and adding dispersing agents or modifiers to create a composite composition that maintains the high volume resistivity of furnace carbon black while improving its dispersion uniformity in the polymer matrix.
3Reliability
If carbon black content is increased to maintain volume resistivity, then volume resistivity is preserved, but surface smoothness deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution of carbon black to maintain adequate volume resistivity at lower carbon black content levels. By using particles in the 0.5-5 μm range with specific surface area (10-50 m²/g), the invention achieves good electrical properties with reduced carbon black loading, thereby improving surface smoothness.
Solution Approach 2:
The patent applies local quality by using smaller carbon black particles (0.5-2 μm) that provide adequate volume resistivity while having less negative impact on surface smoothness. The controlled particle size distribution allows the material to achieve both electrical conductivity and surface quality without requiring high carbon black content.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves a compromise between surface smoothness and volume resistivity, providing improved dispersion and performance in semiconductive applications, particularly in the production of electric power cables.
Implementation Method 1
the carbon black (b) has a mass pellet strength (MPS) according to ASTM D1937-13 of from 50 to 250 N... improved dispersion and performance in semiconductive applications
Data Source
AI summary
The invention provides a novel semiconductive polymer composition with improved smoothness and dispersibility of carbon black when compounding the polymer composition and feasible balance with other properties such as volume resistivity. The semiconductive polymer composition comprises (a) from 30 to 90 wt % of a polymer component, (b) from 10 to 70 wt % of carbon black and the carbon black (b) has a mass pellet strength (MPS) according to ASTM D1937-13 of from 50 to 250 N. The invention further relates to a process for preparing the semiconductive polymer composition comprising the steps of: i) introducing 30-90 wt % of a polymer component as defined above and 0-8 wt % additives in a mixer device and mixing the polymer component and additives at elevated temperature such that a polymer melt is obtained; ii) adding 10-70 wt % of a carbon black as defined above to the polymer melt and further mixing of the polymer melt.